1. Field of the Invention
The present invention relates to a modular jack, and more particularly to a modular jack in a modular connector to be employed in an electronic apparatus such as a telephone and a facsimile machine.
2. Description of Related Art
Conventionally in performing countermeasures for suppressing noise using such a device as a modular jack, as illustrated in FIG. 4, a method of providing a three-terminal capacitor 6 on a circuit board 4 (e.g. printed circuit board) on which a modular jack 2 is mounted is adopted, or as illustrated in FIG. 5, a method of providing a common-mode chock coil 8 on a circuit board 4 on which a modular jack 2 is mounted is adopted.
The three-terminal capacitor 6 has a circuit equivalent to that illustrated in FIG. 6 which is designed for grounding noise components. The common-mode chock coil 8 has a circuit equivalent to that illustrated in FIG. 7 which is designed for offsetting noise components of the same phase by providing two coils opposite to each other around an identical core.
However, the method of using the above three-terminal capacitor 6 has a drawback in that the noise elimination effects is degraded when the electronic apparatus is grounded, i.e. the grounding of the capacitor 6 is insufficient. On the other hand, with the method of using the common-mode chock coil 8 there is no problem with regard to insufficient grounding, however, this method has one drawback int hat the electronic apparatus is less compact because the common-mode chock coil 8 occupies a large space (sometimes the space is equal to or more than that occupied by the modular jack 2) on the circuit board 4.